1. Field of the Invention
The present invention relates to a helical compressor for successively compressing compressive fluid, such as refrigerant in a refrigerating cycle and a method of assembling the helical compressor. More particularly, the present invention relates to a helical compressor having an improved structure for assembling the compressor, a structure for supporting a bearing and a structure for supporting a balancer and a method of assembling the helical compressor.
2. Description of Prior Art
A refrigerating cycle in an air conditioner for heating/cooling a room and in a refrigerator are provided with a compressor which compresses a refrigerant. As a type of compressors of compressing the refrigerant, a helical compressor which has a compression unit operated by a motor and using a helical blade provided therefor has been developed.
In a conventional helical compressor having the helical blade, a sealed case accommodates a helical compression unit and a motor unit, in series, connected to the helical compression unit through a rotating shaft so as to operate the helical compression unit therethrough. The helical compression unit is provided with a cylinder secured to the sealed case and a roller serving as a rotating member which is accommodated at an eccentric position in the cylinder.
The helical compressor also has a helical blade which is interposed between the roller and the cylinder and is wound around a helical groove formed in the outer surface of the roller. A plurality of low-pressure compression chambers are formed between the cylinder and the roller by a dint of the helical blade along the axial direction of the cylinder.
The roller is joined to a crank portion of the rotating shaft, while the rotating shaft is rotatably supported by a main bearing and a sub bearing which close both ends of the cylinder, respectively.
When electric power is supplied to the motor unit, the motor unit is turned on so that the rotor is rotated so that the rotating shaft is rotated. The rotational force of the rotating shaft is transmitted to the crank portion thereof so that the roller is eccentrically rotated. Since the roller is eccentrically rotated, the refrigerant sucked into a low-pressure compression chamber of the cylinder is gradually compressed while helically being moved along the axial direction of the roller. The compressed and helically moving refrigerant is guided from the high pressure compression chamber into the sealed case and passes through a gap formed between the sealed case and the motor unit and so forth, so that the refrigerant is discharged to the outside of the sealed case through a discharge pipe.
In the above conventional helical compressor, the both ends of the cylinder are closed by the main bearing and the sub bearing. The main bearing and the sub bearing rotatably and stably support the rotating shaft which is the output shaft of the motor unit.
However, in the above conventional helical compressor, the motor unit and the helical compression unit, which are accommodated in the sealed case, are disposed while they are separated individually along the axial direction of the rotating shaft. Therefore, since the longitudinal length of the sealed case cannot be shortened, it is difficult to make the helical compressor compact and small.
That is, a vertical type compressor, which is arranged in that the axial direction of the rotating shaft, such as the longitudinal direction, is orthogonal to a horizontal plane, has an excessively large height, and a horizontal type compressor, which is arranged in that the axial direction of the rotating shaft is in parallel with the horizontal plane, requires an excessively large space for installing the horizontal type compressor in the apparatus having the refrigerant cycle, such as air conditioners, refrigerators or other similar apparatus.
As a result of that, in the conventional vertical type and horizontal type compressors, piping elements which must be connected to the conventional compressors cannot easily be assembled, thereby making the apparatuses, each of which has one of the conventional compressors, large.
In the conventional helical compressor, weight unbalance caused from the rotation of the rotating shaft is corrected by a plurality of balancers, for example, not less than 3, attached to portions of the helical compressor, which are positioned exteriorly to a space formed between the main bearing and sub bearing. For example, one of the balancers is attached to the rotor and another of the balancers is attached to the end portion of the rotating shaft, which projects from the sub bearing toward one side opposite to the rotor side.
Since the plurality of individual balancers are attached to the portions positioned exteriorly to the space formed between the main bearing and sub bearing, respectively, the number of the elements constituting the helical compressor cannot be reduced and spaces in the sealed case of the helical compressor are small.
In addition, because the motor unit and the helical compression unit are disposed in the sealed case while they are separated individually along the axial direction of the rotating shaft, the overall length of the rotating shaft is long.
Therefore, the number of the balancers, which are attached to the portions positioned exteriorly to the space formed between the main bearing and sub bearing, are large, so that the process for attaching each of the large number of the balancers takes a long time and is complicated.
On the other hand, it is true that the rotating shaft is stably supported by the main bearing and the sub bearing.
However, because the motor unit and the helical compression unit are disposed in the sealed case while they are separated individually along the axial direction of the rotating shaft, it is difficult to align a center axial direction of the rotating shaft with center axial directions of the main and sub bearings.
More particularly, due to using the two bearings (main bearing and sub bearing), it needs to align the center axial directions of the two main and sub bearings each other. Thus, an additional process for aligning the center axial directions of the main and sub bearing must be performed when the helical compressor is assembled, whereby it takes a long time for assembling the helical compressor.